Safety construction

Safety Helmet ( Hard Hat )
You Shall be wear safety helmet when go to construction area for protect your head from impact, or from falling or flying objects, or from electrical shock and burns.


Standard of Safety Helmet

ANSI Z89.1-1986

ANSI Z89.1-1986 separates protective helmets into different types and classes.

The standard identifies Type 1 and Type 2 helmets. Type 1 helmets incorporate a full brim (the brim fully encircles the dome of the hat); Type 2 helmets have no encircling brim, but may include a short bill on the front (similar to a baseball cap).

In terms of electrical performance, ANSI Z89.1-1986 recognizes three classes:

• Class A Helmets are intended to reduce the force of impact of falling objects and to reduce the danger of contact with exposed low-voltage electrical conductors. For certification, sample shells are proof-tested at 2,200 volts of electrical charge.
• Class B Helmets are intended to reduce the force of impact of falling objects and to reduce the danger of contact with exposed high-voltage electrical conductors. Sample shells are proof-tested at 20,000 volts.
• Class C Helmets are intended to reduce the force of impact of falling objects, but offer no electrical protection.

Note: The voltages stated in Classes A and B are not intended to be an indication of the voltage at which the headgear protects the wearer.

In addition to electrical protection, hard hats are also tested for impact and penetration resistance from blows to the top of the head, flammability resistance, and water absorption. The rigorous testing requirements are described in detail within the standard.

Every hard hat conforming to the requirements of ANSI Z89.1-1986 must be appropriately marked to verify its compliance. The following information must be marked inside the hat:

•The manufacturer's name
•The legend, "ANSI Z89.1-1986"
•The class designation (A, B or C)

ANSI Z89.1-1997

In 1997 ANSI published a revision to its Z89.1 head protection standard. ANSI Z89.1 contains some notable changes.

The revision eliminated the old Type 1 and Type 2 design designations. In the revised standard, "Type" is used to designate whether a helmet provides protection strictly from blows to the top of the head (Type I) or protection from blows to both the top and sides of the head (Type II).

In addition, Z89.1-1997 also changed the alpha designations for the classes of electrical performance. Under Z89.1-1997, the following three classes are recognized:

• Class G (General) Helmets--This is equivalent to the old Class A. Class G helmets are proof tested at 2,200 volts.
• Class E (Electrical) Helmets--This is equivalent to the old Class B. Class E helmets are proof tested at 20,000 volts.
• Class C (Conductive) Helmets--This class provides no electrical insulation; the alpha designation did not change from the old standard.

Hard hats must also contain user information under the 1997 standard. In addition to the manufacturer's name, ANSI legend and class designation, Z89.1-1997 compliant helmets must be marked with the date of manufacture. Instructions pertaining to sizing, care and service life guidelines must also accompany the hard hat.

ANSI Z89.1-2003

ANSI published a revision to the Z89.1-1997 standard in 2003. The most significant changes from the 1997 version were made to harmonize with other national standards that test and evaluate equipment performance. In addition, many physical requirements for helmet components that do not provide added user value or that limited design or performance have been removed.